Blackout: This is unexpected discontinuation of power supply in the laboratory.

Power sag: Sudden drop of voltage levels that lasts less than a second.

Transients/ surge: High voltage flowing.

Brownout: Partial blackout where there's low voltage flow.

• data must be up to date
•  data can only be read/used for the purpose for which it was collected
• data must be adequate, relevant and not excessive
• data must be accurate
• data must be destroyed when no longer needed/don’t keep longer than necessary
• data user must register what data stored
• data must be used/collected fairly and lawfully
• data must be held securely
• data must be protected from accidental damage
• only authorised personnel can have access to the data
• fines are imposed for data mis-use
• data should not be passed on to a third party without permission
• a person can view data and have it changed/removed if incorrect

(a) Disk mirroring- Data is written on two or more disks simultaneously.

(b) Encryption - Contents are scrambled so they cannot be understood without a decryption key

(c) Backup - A copy of the data is taken and stored in another location

• compact disks
• DVDs
• Blue Ray

https :  protocol

google.co.ke: domain name

/index.html: webpage/file name

Advantages

•  A touch screen is very intuitive
• Easy to use as the user simply touches what they see on the display
• Save space as no keyboard or mouse is required.
• Touch monitors can even be mounted on the wall.
• Touching a visual display of choices requires little thinking and is a form of direct manipulation that is easy to learn.
• Touch screens are the fastest pointing devices.
• Touch screens have easier hand-eye coordination than mice or keyboards.
• No extra workspace is required as with other pointing devices.
• Touch screens are durable in public access and in high volume usage

Disadvantages

• Difficult for people with accessibility issues, e.g no feedback, disability
• Can be easily damaged/scratched
• Damaged/scratched screen prevent the interface from functioning as it should
• Dirty screens difficult to read
• Users must be within arm’s reach of the display
• It is difficult to select small items
• User's hand may obscure the screen
• Screens need to be installed at a lower position and tilted to reduce arm fatigue
• Some reduction in image brightness may occur
• They cost more than alternative devices

method of transmission e.g

• blue tooth
• radio
• optical
• satellite
• infra-red
• microwave

device e.g.

• 3G (WAP) mobile phones/mobile phones/cell phone/remote
• key pad/remote control/keyboard
• infra-red mouse
• multimedia mobile handsets/notebooks
• GPRS (general packet radio service) mobiles
• WLAN(or WiFi) hotspots sited in public areas - e.g. coffee
• shops, railway stations, airports, motorway services
• linked printers
• PDA's (personal digital assistants)
• GPS

• Broadcast Radio
• Infrared
• Bluetooth
• Microwaves
• Satellite

Multi-tasking - It is a data processing modes where a single CPU processing more than one task or program apparently at the same time

Time-sharing - a processing mode where a single CPU processes tasks from more than one user apparently at the same time

Time-sharing - this is a processing mode in which the CPU serves two or more users with different processing requirements ( tasks)

On-line processing - is a mode of processing where the result of data processing transaction is available immediately

Real-time processing - is a mode of data processing in which the time interval required to process and respond to inputs is so small that the response itself is useful for controlling the physical activity of a process

1. Hardware failure
2. Corrupted software files
3. Hacking into the system
4. Power failure

• It has electrical components.
• It is programmable.

• loss of jobs as some traditional shops/banks close
• lower profits for companies that do not get involved with e-commerce
• decline of leisure shopping as goods are bought on-line
• city centres becoming deserted as shops/banks close down
• gap between rich and poor widening as richer get savings from
• shopping on-line
• more people choosing to interact with computers rather than people
• increase in small businesses
• less pollution/travelling

• not able to directly manipulate the hardware
• may need to wait for translation before running
• the program may be less efficient.

• consists of values between 0–255 / 0–FFF
• values are separated by full stops/colons
• it is a unique address
• can be static or dynamic
• can be public or private
• can be IPv4 / have four groups of digits
• can be IPv6 / have eight groups of digits
• in IPv6: can replace groups of zeros.

• Optical scanner is used read data by use a beam of light while a magnetic ink scanner is used to read data encoded/written using magnetic ink by magnetising the ink characters and translating them

highest = -1
for student = 1 to 3000
total = 0
for exam = 1 to 8
input mark
total = total + mark
if mark > highest then highest = mark
next
average = total/8
output average
next
output highest

Python code:

highest = -1
for student in range(1, 3001):
    total = 0
    for exam in range(1, 9):
        mark = int(input("Enter mark: "))
        total += mark
        if mark > highest:
            highest = mark
    average = total / 8
    print("Average:", average)
print("Highest mark:", highest)

VBA Code

Option Explicit

Sub CalculateAverageAndHighest()
    Dim highest As Integer
    Dim total As Integer
    Dim mark As Integer
    Dim average As Double
    
    highest = -1
    
    For student = 1 To 3000
        total = 0
        For exam = 1 To 8
            mark = InputBox("Enter mark:")
            total = total + mark
            If mark > highest Then
                highest = mark
            End If
        Next exam
        average = total / 8
        MsgBox "Average: " & average
    Next student
    
    MsgBox "Highest mark: " & highest
End Sub

• where the new system is completely different from the old one
• if there has been extensive testing of the system and the system analyst has confidence in its functionality
• If the system is not critical

(i) the potential health hazards of this type of work,

• backstrain due to long periods of immobility
• eye strain due to long periods of staring  at the screen
• RSI- continual use of the same muscle group

(ii) the ways that management can help to overcome the effects of the health hazards.

• Move around regularly
• use ergonomic chair
• use anti-glare screen
• use of wrist pads

• colour codes // colour in HTML/CSS
• error messages
• locations in memory
• memory dump // debugging 
• IP(v6) address
• ASCII // Unicode
• assembly language
• URL.

• devices are automatically detected and configured when initially attached
• Impossible to connect device incorrectly/connector only fits one way
• has become the industry standard
• supports multiple data transmission speeds
• lots of support base for USB software developers
• supported by many operating systems
• backward compatible
• faster transmission compared to wireless